1. Technical Field
The invention relates to technology for driving a discharge lamp.
2. Related Art
For the discharge lamp used for the light source of a projector (projection device), known are high intensity discharge lamps (HID lamps) such as high pressure mercury lamps, metal halide lamps, high pressure sodium lamps and the like. Generally, the discharge lamp for a projector receives a supply of alternating current (AC), and emits light by an arc discharge generated between two electrodes. Projecting parts that become the arc origin point are formed at each of the electrodes of the discharge lamp to stabilize the arc discharge between the electrodes. The shrinkage or loss of the projecting part at the electrode is a cause of flicker or arc jump. The flicker is the phenomenon of the light emitted from the discharge lamp blinking, and the arc jump is the phenomenon of the illuminance of the light emitted from the discharge lamp decreasing due to the arc origin point moving and the arc length becoming longer.
In the past, to prevent the shrinkage or loss of the projecting part which becomes a cause of flicker and arc jump, technology was proposed for maintaining the projecting part by adjusting the electrode temperature.